1. Field of the Invention
The present invention relates to a slide fastener for use on a bag, for example, made of paper or nonwoven fabric to open and close an opening in the bag.
2. Description of the Prior Art
Prior slide fasteners for attachment to bags of paper or nonwoven fabric comprise stringer tapes of paper or nonwoven fabric supporting rows of coupling elements directly thereon. When such a slide fastener is subjected to transverse forces tending to pull the stringer tapes laterally apart, the stringer tapes are liable to be torn apart before the rows of coupling elements are disengaged from each other. The slide fastener is usually attached to a paper bag or a nonwoven-fabric bag by stitching the stringer tapes to edges of the bag across an opening therein. Since the stringer tapes are perforated by the sewing needle, however, they become weak in mechanical strength. Another problem with the known slide fasteners having a paper or nonwoven-fabric tape is that it is relatively tedious and time-consuming to attach the slide fastener to a desired object.